1. Field of the Invention
This invention relates generally to telecommunications, and, more particularly, to wireless communications.
2. Description of the Related Art
In the field of wireless telecommunications, such as cellular telephony, a system typically includes a plurality of base stations distributed within an area to be serviced by the system. Various users within the area, fixed or mobile, may then access the system, and, thus, other interconnected telecommunications systems, via one or more of the base stations. Typically, a mobile device maintains communications with the system as the mobile device passes through an area by communicating with one and then another base station, as the user moves. The mobile device may communicate with the closest base station, the base station with the strongest signal, the base station with a capacity sufficient to accept communications, etc.
Many mobile devices are programmed by a service provider with a 10-digit, unique subscription identifier called a Mobile Identification Number (MIN). In particular, service providers in the United States utilize MIN, rather than the International Mobile Subscriber Identity (IMSI). The MIN may be used by the service provider to validate, provide customized service, and bill correctly. However, there are several shortcomings associated with the use of MIN. For example, with the explosion of cellular telephony, the number of unique MINs is in danger of being exhausted. Further, there is no international standard for MIN usage, and thus, international roaming standards do not support MIN. For example, a mobile device using MIN cannot roam to a cellular system that employs IMSI.
Migrating away from a fully implemented MIN based system to an IMSI based system is fraught with transitional difficulties. For example, implementation requires coordination of changes to network elements within and beyond a service provider's own network, including the network elements of the service provider's roaming partners and international SS7 transport networks. Further, programming of new and existing mobile devices and back office operational systems must also be implemented. A lack of coordination in any of these changes can create huge difficulties in the wireless system as a whole, potentially shutting down or at least temporarily reducing the capabilities of the wireless system.